     (doseq [v base-set-1,
             r R,
             :when (not (empty? (.get remove [v r])))]
-      (.add non-empty-removes [v r]))
-    (while-let [[v r] (first non-empty-removes)]
-      (doseq [u (pre-1 v r),
-              w (.get remove [v r])]
+      (.addFirst non-empty-removes [v r]))
+    (while-let [[v r] (.peekFirst non-empty-removes)]
+      (doseq [w (.get remove [v r]),
+              u (pre-1 v r)]
         (when (contains? (.get sim u) w)
           (.put sim u
                 (disj (.get sim u) w))

        conexp.contrib.dl.framework.semantics
        conexp.contrib.dl.util.graphs)
  (:use clojure.contrib.pprint)
  (:import [java.util HashMap HashSet]))

(ns-doc
 "Implements description graphs and common operations on them.")

            (when (empty? (intersection (.get sim u) (post-2 w* r*)))
              (.put remove [u r*]
                    (conj (.get remove [u r*]) w*))
              (.addLast non-empty-removes [u r*])))))
      (.put remove [v r] #{})
      (.removeFirst non-empty-removes))
    (HashMap->hash-map sim)))


